Abstract: A transportable combustion air heater comprises a transportable supporting frame, a housing fixed to the frame, a cylindrical combustion chamber arranged in housing, a cylindrical annular thermal exchange channel formed around the combustion chamber, an external heating chamber defining an annular fume channel around the thermal exchange channel, in which one or more transversal guide walls are arranged in the external heating chamber, which guide walls lengthen flow paths of the fumes in the annular fume channel from fume inlet openings to an exhaust fume opening.

Abstract: A movable fluid fuel heater to heat air and to introduce it into an environment to be heated. The heater includes a flow rate variator device for varying the flow rate of oxidizing air introduced in the combustion chamber by a forced ventilation device between a minimum flow rate value and a maximum flow rate value. The heater also includes a reference device comprising a plurality of reference values of a parameter representative of the pressure and a plurality of reference temperature values of the environmental air upstream of the combustion chamber. The reference device is configured to suggest an optimal setting value to set the flow rate variator device, at each pair of values formed by a value of the plurality of reference values of a parameter representative of the pressure and a value of the plurality of reference temperature values.